Embanking arrangement

ABSTRACT

Disclosed is an embanking arrangement for separating and protecting a first water volume from a second water volume, including a barrier connected to land and having an opening, a stationary basis extending across the opening, and a mobile port arrangement including a hull delimiting an inner tank. The embanking arrangement takes closed and open states respectively, wherein the inner tank of the port arrangement is at least partly filled with water and the hull of the port arrangement is standing on the basis when the embanking arrangement is in the closed state. The port arrangement is floating in the open state. The port arrangement includes at least a first opening connecting the inner tank and the first water volume, and including a controllable valve, and a pump connected with the second water volume to transport water from the first water volume to the second water volume.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to an embanking arrangement for protecting areas that are threatened by floods due to storms or due to other temporary water level rise at sea, rivers and lakes.

The present invention relates especially to an embanking arrangement for separating and protecting a first water volume from a second water volume. The embanking arrangement comprising a barrier connected to land and having an opening, said opening allowing fluid communication and passage between the first water volume and the second water volume, a stationary basis extending across said opening, and a mobile port arrangement comprising a hull delimiting an inner tank. The embanking arrangement is configured to take a closed state by letting water flowing into the inner tank of the port arrangement such that the buoyancy of the port arrangement is decreased and the port arrangement sinks towards the stationary basis, preventing free passage between the first water volume and the second water volume in the closed state, and is configured to take an open state allowing free passage between the first water volume and the second water volume, wherein the inner tank of the port arrangement is at least partly filled with water and the hull of the port arrangement is located standing on said basis when the embanking arrangement is in the closed state, and wherein the port arrangement is located at a distance from said basis when the embanking arrangement is in the open state by restoring the buoyancy of the port arrangement by pumping out water from the inner tank of the port arrangement.

BACKGROUND OF THE INVENTION AND PRIOR ART

It is a known fact that the sea levels around the world are rising due to climate changes and they are expected to rise even more in the future. This entails less safety margins especially in coastal communities and thereto an increased risk for temporary floods, especially related to storms. In connection with storms the rough winds force up the water level, and thereto the water rise due to the low air pressure. The mean water level at sea may rise about 2-3 meters or more above normal. The high water situations are often temporary, usually less than 24 hours but may also continue one or more days, causing a need for a temporary protection. Thus, due to rising sea levels many coastal communities are threatened to be flooded during extreme high water situations, when winds, air pressure and also tide interacts.

In the long-term permanent embankments may be necessary if the sea levels continue to rise, but the need for such permanent embankments can be postponed another 100-200 years ahead if the problem of temporary floods is solved.

For this reason defenses/embanking arrangements in the form of protective sea walls have already been built in many places, such as in London, St Petersburg and Rotterdam, while the work of building sea walls are in progress at other places, such as Venice. Discussions regarding the need for building similar defenses/embanking arrangements are in progress at several places, inter alia Gothenburg, Stockholm, Copenhagen and New York. The problem exists also at some places in connection with rivers and lakes, for instance in Arvika (Sweden), but in these areas it is rain and/or melted snow that threatens to rise the water levels.

One drawback of known projects is that they tend to be very expensive, partly because the floodgates often need to be big enough to allow commercial shipping when not closed, partly because it is technically complicated to build large and permanent mechanical structures that must be extremely reliable as well.

In the patent literature, WO 03/057995, it is known to use a long and narrow ship-like port arrangement in embanking arrangements, wherein the ship-like port arrangement can be lowered at an opening in the barrier connected to land by being filled with water. The ship-like port arrangement in said document comprises several mutually separated sections, wherein each section can be filled with water from the water volume/area facing the specific section and thereto be emptied from water to the same water volume/area facing the specific section. By means of the proposed solution you may get away from the problem of expensive and complicated permanent mechanical structures.

One remaining problem of the above mentioned solution is how to handle the water filling up the protected water area from rivers and rain. Many seaports are located at the mouth of a river, and if you block the inflow of water from the sea you will also block the outflow of river water to the sea, this might result in the city becoming flooded by river water, despite the water level in the protected water area is lower than the water level at the sea side of the embanking arrangement.

OBJECT OF THE INVENTION

The present invention aims at obviating the aforementioned disadvantages and failings of previously known embanking arrangements, and at providing an improved embanking arrangement. A primary object of the present invention is to provide an improved embanking arrangement of the initially defined type, which is a simple and cheap way to protect the area that is threatened to become flooded due to rising water level in the second water volume.

It is another object of the present invention to provide an embanking arrangement, which at the same time protects the area that is threatened to become flooded due to rising water levels also in the first water volume.

It is another object of the present invention to provide an embanking arrangement, which does not need external maneuvering in connection with the embankment being established/erected and terminated, respectively.

BRIEF DESCRIPTION OF THE INVENTION

According to the invention at least the primary object is attained by means of the initially defined embanking arrangement, having the features defined in the independent claim. Preferred embodiments of the present invention are further defined in the dependent claims.

According to the present invention, there is provided an embanking arrangement of the initially defined type, which is characterized in that the port arrangement comprises at least a first opening in the hull, said first opening connecting the inner tank of the port arrangement and the side of the port arrangement facing the first water volume, said first opening comprising a controllable valve that in open state allows fluid communication through said first opening, and at least one pump, said pump being arranged in connection to the side of the port arrangement facing the second water volume and being configured to transport water from the first water volume to the second water volume.

Thus, the present invention is based on the insight that the embanking arrangement can solve far more problems than previous attempted solutions and thereto solves the problems the known attempted solutions create, by allowing to transport water from the protected water volume to the outside water volume despite the water level in the protected water volume is lower than the water level in the outside water volume.

According to a preferred embodiment of the present invention, the port arrangement comprises at least one channel, said channel extending from the side of the port arrangement facing the first water volume to the side of the port arrangement facing the second water volume, and said at least one pump being arranged in said channel. According to an alternative embodiment said pump is configured to transport water from the first water volume to the second water volume via the inner tank of the port arrangement and via the first opening of the hull.

Further advantages with and features of the invention will be apparent from the other dependent claims as well as from the following detailed description of preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the abovementioned and other features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments in conjunction with the appended drawings, wherein:

FIG. 1 is a schematic illustration of a harbor entrance wherein the embanking arrangement is in the open state and the port arrangement is located next to the opening in the barrier connected to land, i.e. allowing free passage,

FIG. 2 is a schematic illustration of the harbor entrance according to FIG. 1, wherein the water from the harbor, usually river water, flows into the sea,

FIG. 3 is a schematic illustration of the harbor entrance according to FIG. 1, wherein the sea level rises and the sea water flows into the harbor,

FIG. 4 is a schematic illustration of the harbor entrance according to FIG. 1, wherein the embanking arrangement is in the closed state and the port arrangement is located across the opening in the barrier connected to land, i.e. preventing free passage,

FIG. 5 is a schematic cross section of the port arrangement and the barrier connected to land taken along A in FIG. 2,

FIG. 6 is a schematic cross section of the port arrangement and the barrier connected to land taken along B in FIG. 2,

FIG. 7 is a schematic cross section of the port arrangement and the opening of the barrier connected to land taken along C in FIG. 4, wherein the port arrangement is standing on the basis,

FIG. 8 is a schematic cross section of the port arrangement and the opening of the barrier connected to land taken along C in FIG. 4, wherein the port arrangement is floating, i.e. at a distance from the basis,

FIG. 9 is a schematic cross section of the port arrangement and the opening of the barrier connected to land taken along C in FIG. 4, wherein lowering of the port arrangement is in progress,

FIG. 10 is a schematic cross section of the port arrangement and the opening of the barrier connected to land taken along C in FIG. 4, wherein the port arrangement is standing on the basis and water is transported from the first water volume to the second water volume, and

FIG. 11 is a schematic cross section of the port arrangement according to an alternative embodiment and the opening of the barrier connected to land taken along C in FIG. 4, wherein the port arrangement is standing on the basis and water is transported from the first water volume to the second water volume.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The present invention relates in general to an embanking arrangement configured to protect an area that is threatened to be flooded during storms or during other temporary water level rises at sea, rivers and lakes.

Reference is initially made to FIGS. 1-7. The inventive embanking arrangement is configured to separate and protect a first water volume 5 from a second water volume 6. The first water volume 5 is the water area/harbor that shall be protected from too big water level rises, and the second water volume is the water area/sea wherein the water level rises uncontrollably.

The embanking arrangement comprises a barrier 4 connected to land/shore and having an opening 3. The barrier 4 connected to land, also known as embankment, is preferably stationary and is preferably constituted by a concrete structure. The opening 3 in the barrier 4 connected to land allows fluid communication and passage of sea traffic between the first water volume 5 and the second water volume 6. The embanking arrangement also comprises a stationary basis 2 extending across said opening 3, in other words the stationary basis 2 connects the two halves of the barrier 4 connected to land. The basis 2, or the bed, is preferably a concrete structure, by can also be constituted by a natural sea/river bed prepared with natural material/stones, or a frame work of metal beams lowered into the sea bed or lake bed, wherein the upper surface of the frame work has the same geometrical shape as the lower side of the hull, or a combination thereof. The basis 2 shall be mainly plane and horizontal.

It is essential for the inventive embanking arrangement that is comprises a mobile port arrangement 1, in FIGS. 1-3 located/moored adjacent to or at a distance from the opening 3. The mobile port arrangement 1 comprises a hull delimiting an inner tank, which in an empty state comprises air and which in a filled state comprises water. The port arrangement 1 is in the disclosed embodiments constituted by a ship-like craft.

The embanking arrangement is configured to take a closed state, as is shown in FIGS. 4 and 6-7, wherein free passage and fluid communication between the first water volume 5 and the second water volume 6 is blocked, and an open state, as is shown in FIGS. 2 and 5, wherein at least fluid communication between the first water volume 5 and the second water volume 6 is allowed. When the embanking arrangement is in the closed state the inner tank of the port arrangement 1 is at least partly filled with water and the hull of the port arrangement is located standing on said basis 2, whereupon the port arrangement 1 prevents fluid communication between the first water volume 5 and the second water volume 6. When the embanking arrangement is in the open state the port arrangement 1 is located at a distance from the basis 2, preferably beside the opening 3, and fluid communication between the first water volume 5 and the second water volume 6 is allowed. When the port arrangement 1 is located beside the opening 3 free passage of sea traffic is allowed. The port arrangement 1 may also be located at another place when the embanking arrangement is in the open state.

It shall be pointed out that the port arrangement 1 can be arranged in a lowered state also when the port arrangement 1 is located beside the opening 3 in the barrier 4 connected to land.

FIG. 8 disclose the port arrangement 1, located across the opening 3 in the barrier 4 connected to land between the protected first water volume 5 and the outer second water volume 6, but still in a floating (not filled with water) state. In other words free passage of sea traffic is prevented through the opening 3 at the same time as fluid communication through the opening 3 is allowed. The port arrangement 1 is still not in contact with the basis/bed 2.

FIG. 9 disclose the port arrangement 1 in the same position as in FIG. 8, but the lowering has been started by having at least one first opening 7 in the hull opened in order to let in water into the inner tank of the port arrangement 1. The first opening 7 connects the inner tank of the port arrangement 1 and the side of the port arrangement 1 facing the first water volume 5, said first opening 7 comprising a controllable valve (gate) that in open state allows fluid communication through said first opening 7. Preferably, the first opening 7 shall be located as far down as possible. Preferably the port arrangement 1 comprises several first openings 7. When the port arrangement 1 comes in contact with and is standing on the basis 2 the first opening 7 may remain open, whereupon the water level in the inner tank is the same as the water level in the first water volume 5. Preferably the first opening 7 is closed when a suitable amount of water is brought into the inner tank, and thereby a predetermined pressure result between the port arrangement 1 and the basis 2.

In FIG. 9 also at least one second opening 7′ in the hull of the port arrangement 1 is opened in order to speed up the lowering of the port arrangement 1. The second opening 7′ is optional. The second opening 7′ connects the inner tank of the port arrangement 1 and the side of the port arrangement 1 facing the second water volume 6, said second opening 7′ comprising a controllable valve (gate) that in open state allows fluid communication through said second opening 7′. Preferably, the second opening 7′ shall be located as far down as possible. Preferably the port arrangement 1 comprises several second openings 7′. When the port arrangement 1 comes in contact with and is standing on the basis 2 the second opening 7′ is closed.

FIGS. 10 and 11 disclose the port arrangement 1 in the same position as in FIGS. 8 and 9, but now at least partly filled with water and in lowered position. The port arrangement is now standing on the basis 2 as well as in contact with the barrier 4 connected to land, implying that the water flow from the second water volume 6 to the protected first water volume 5 is blocked. The first opening 7 in the hull is still open, while the second opening 7′ in the hull is closed.

The inventive port arrangement 1 comprises further at least one pump 8, said pump 8 being arranged in connection with the side of the port arrangement 1 facing the second water volume 6 and being configured to transport water from the first water volume 5 to the second water volume 6.

According to the embodiment disclosed in FIG. 10 the port arrangement 1 comprises at least one channel 9, said channel 9 extending from the side of the port arrangement 1 facing the first water volume 5 to the side of the port arrangement 1 facing the second water volume 6, and said at least one pump 8 being arranged in said channel 9. Thereto it is preferred that said at least one channel 9 comprises at least a first controllable valve 10 (gate) configured to prevent a flow of water in the direction from the second water volume 6 to the first water volume 5. The first controllable valve 10 is in the disclosed embodiment located at the side of the port arrangement 1 facing the second water volume 6. In the disclosed embodiment the channel 9 comprises also a second controllable valve 10′ (gate) that in the disclosed embodiment is located at the side of the port arrangement facing the first water volume 5. It shall be pointed out that the channel 9, more precisely the first controllable valve 10 and the second controllable valve 10′, are closed in FIGS. 8 and 9. In FIG. 10 the channel 9 is open, more precisely the first controllable valve 10 and the second controllable valve 10′ are open and the pump 8 pumps/transports water through the channel 9 from the first water volume 5 to the second water volume 6. This is performed since the water level in the first water volume 5 shall not rise due to inflow from rivers and rain that otherwise will cause flooding despite the water level in the first water volume 5 is lower than the water level in the second water volume 6. Thus, if the area of the first water volume 5 is small in relation to the amount of fresh water that inflows from rivers and rain, the seaport risks to be flooded if the barrier is closed.

According to the alternative embodiment disclosed in FIG. 11 said pump 8 is configured to transport water from the first water volume 5 to the second water volume 6 via the inner tank of the port arrangement 1 and via the first opening 7 of the hull. Thus, the channel 9 according to FIG. 10 can be spared. However, a first controllable valve 10 (gate), preventing a flow of water from the second water volume 6 to the inner tank of the port arrangement 1 when the pump 8 is not active, must be present.

If the habor entrance is also exposed to tide the situation may occur that during low tide the water level in the second water volume/sea 6 during a few hours, despite higher than normal, still is lower than the water level in the protected first water volume 5. Then the water level in the first water volume 5 can be maintained or the water level in the first water volume 5 can be lowered by for instance having the first opening 7 and the second opening 7′, that are used during the original filling with water, temporarily opened in order to increase the outflow capacity from the first water volume 5 to the second water volume 6.

Thus, the filling of the port arrangement 1 with water takes place in a simple and quick way by opening big gates (7, 7′) in the hull and letting sea water flowing into the inner tank of the port arrangement 1. The port arrangement 1 sinks and the preferably plane bottom of the port arrangement 1 is placed on the preferably plane basis 2 that has been provided under the opening 3 in the permanent embankment/barrier 4. The weight of the port arrangement 1, in combination with the decreased buoyancy that the water in the inner tank entails, provides a necessary weight against the basis 2 such that the frictional force makes it possible for the port arrangement 1 to remain standing when it is exposed to transversal loads from both the increased water level in the second water volume 6 and from waves and wind. However, it is preferred that the port arrangement 1 is moored to the barrier 4 connected to land.

The frictional force can be increased further by decreasing the water pressure between the bottom/lower side of the port arrangement 1 and the basis 2. The water pressure is decreased by decreasing the contact area between the port arrangement 1 and the basis 2, for instance by providing the lower side of the port arrangement 1 and/or the basis 2 with means configured for draining away water from the first water volume 5 leaking under the port arrangement. Preferably this is accomplished by means of transversal grooves in either the lower side of the port arrangement 1 or the basis 2.

Preferably, said pump 8 is also configures for propelling and/or maneuvering of the port arrangement 1 when the inner tank of the port arrangement 1 is empty. In the case the port arrangement 1 comprises several pumps 8, one or more of these pumps 8 must also be able to pump water out of the port arrangement 1 when the case of danger is over and/or when the water level in the second water volume 6 has sunk to normal levels, in order to get the port arrangement 1 floating again. In some cases it can be possible to temporarily, for instance during low tide, to pump out as much water as needed to have the port arrangement 1 to lift from the basis 2 and thereby allowing water from the first water volume 5 by its own force flow through the opening 3 underneath the port arrangement 1.

It shall be pointed out that the water being pumped out of the inner tank of the port arrangement 1, either in order to increase the buoyancy of the port arrangement 1 or in order to evacuate water from the first water volume 5 to the second water volume 6, not necessarily needs to be transported through the mid-section of the port arrangement 1, perpendicular to its longitudinal direction. The water can also be pumped out of or next to the fore or stern of the port arrangement 1. Pumps 8 directing the flow of water in the longitudinal direction of the port arrangement 1, or in close angle thereto, can also be used for propelling the port arrangement 1 in the forward or backward direction, as well as for steering and maneuvering.

The advantage of using a ship-like port arrangement 1 as embankment (mobile gate) is not only the fact that it can transport itself to the location where it shall be lowered, but also that it can be configured for other purposes the considerably longer time it does not serve as an embanking device. Instead, the port arrangement 1 can, also at another location, serve as a car park, restaurant, car ferry, floating bridge, etc., opening up for new funding opportunities and a better total economy. At many seaports the centrally located land is expensive, and a port arrangement 1 moored to the dock in the middle of the town can provide additional valuable square meters. A 150 meters long and 25 meters wide hull may for instance serve as a car park having about 300 parking places. The income from such business may be crucial way to improve the total economy of the embanking project. The port arrangement 1 must in such cases comprise storage space above the inner tank, said storage space being configured to be connected to the dock or the barrier 4 connected to land by means of temporary gangways.

Also other fields of application are possible. The storage space of the port arrangement 1 may on ordinary days be used as warehouse for various materials, or as a car ferry, or a floating bridge. The only requirement is that it in a relatively short notice (less than 24 hours) can be made ready for its main function as embanking device, be moved to the location of service and be activated by being filled with water.

The port arrangement 1 could also be used such other purposes also when it is located at the barrier 4 connected to land. Such a use is at least as temporary road connection, by having a roadway applied to the barrier 4 connected to land and temporarily connected to the deck or storage space of the port arrangement 1 via temporary gangways. The road connection can be used both when the port arrangement 1 is in the lowered state and in the floating state.

FEASIBLE MODIFICATIONS OF THE INVENTION

The invention is not limited only to the embodiments described above and shown in the drawings, which primarily have an illustrative and exemplifying purpose. This patent application is intended to cover all adjustments and variants of the preferred embodiments described herein, thus the present invention is defined by the wording of the appended claims and thus, the equipment may be modified in all kinds of ways within the scope of the appended claims.

It shall also be pointed out that all information about/concerning terms such as above, under, upper, lower, etc., shall be interpreted/read having the equipment oriented according to the figures, having the drawings oriented such that the references can be properly read. Thus, such terms only indicates mutual relations in the shown embodiments, which relations may be changed if the inventive equipment is provided with another structure/design.

It shall also be pointed out that even thus it is not explicitly stated that features from a specific embodiment may be combined with features from another embodiment, the combination shall be considered obvious, if the combination is possible. 

1-6. (canceled)
 7. An embanking arrangement for separating and protecting a first water volume (5) from a second water volume (6), comprising: a barrier (4) connected to land and having an opening (3), said opening (3) allowing fluid communication and passage between the first water volume (5) and the second water volume (6), a stationary basis (2) extending across said opening (3), and a mobile port arrangement (1) comprising a hull delimiting an inner tank, the embanking arrangement being configured to take a closed state by letting water flowing into the inner tank of the port arrangement (1) such that the buoyancy of the port arrangement (1) is decreased and the port arrangement (1) sinks towards the stationary basis (2), preventing free passage between the first water volume (5) and the second water volume (6) in the closed state, and being configured to take an open state allowing free passage between the first water volume (5) and the second water volume (6), wherein the inner tank of the port arrangement (1) is at least partly filled with water and the hull of the port arrangement (1) is located standing on said basis (2) when the embanking arrangement is in the closed state, and wherein the port arrangement (1) is located at a distance from said basis (2) when the embanking arrangement is in the open state by restoring the buoyancy of the port arrangement (1) by pumping out water from the inner tank of the port arrangement (1), characterized in that the port arrangement (1) comprises: at least a first opening (7) in the hull, said first opening (7) connecting the inner tank of the port arrangement (1) and the side of the port arrangement (1) facing the first water volume (5), said first opening (7) comprising a controllable valve that in open state allows fluid communication through said first opening (7), and at least one pump (8), said pump (8) being arranged in connection to the side of the port arrangement (1) facing the second water volume (6) and being configured to transport water from the first water volume (5) to the second water volume (6) through the hull of the port arrangement (1).
 8. The embanking arrangement according to claim 7, wherein the port arrangement (1) comprises at least one channel (9), said channel (9) extending from the side of the port arrangement (1) facing the first water volume (5) to the side of the port arrangement (1) facing the second water volume (6), and said at least one pump (8) being arranged in said channel (9).
 9. The embanking arrangement according to claim 8, wherein said at least one channel (9) comprises a first controllable valve (10) configured to prevent a flow of water in the direction from the second water volume (6) to the first water volume (5).
 10. The embanking arrangement according to claim 7, wherein said pump (8) is configured to transport water from the first water volume (5) to the second water volume (6) via the inner tank of the port arrangement (1) and via the first opening (7) of the hull.
 11. The embanking arrangement according to claim 7, wherein the port arrangement (1) comprises: at least a second opening (7′) in the hull, said second opening (7′) connecting the inner tank of the port arrangement (1) and the side of the port arrangement (1) facing the second water volume (6), said second opening (7′) comprising a controllable valve that in open state allows fluid communication through said second opening (7′).
 12. The embanking arrangement according to claim 7, wherein said pump (8) is configured for propelling and/or maneuvering of the port arrangement (1) when the inner tank of the port arrangement (1) is empty.
 13. The embanking arrangement according to claim 8, wherein the port arrangement (1) comprises: at least a second opening (7′) in the hull, said second opening (7′) connecting the inner tank of the port arrangement (1) and the side of the port arrangement (1) facing the second water volume (6), said second opening (7′) comprising a controllable valve that in open state allows fluid communication through said second opening (7′).
 14. The embanking arrangement according to claim 9, wherein the port arrangement (1) comprises: at least a second opening (7′) in the hull, said second opening (7′) connecting the inner tank of the port arrangement (1) and the side of the port arrangement (1) facing the second water volume (6), said second opening (7′) comprising a controllable valve that in open state allows fluid communication through said second opening (7′).
 15. The embanking arrangement according to claim 10, wherein the port arrangement (1) comprises: at least a second opening (7′) in the hull, said second opening (7′) connecting the inner tank of the port arrangement (1) and the side of the port arrangement (1) facing the second water volume (6), said second opening (7′) comprising a controllable valve that in open state allows fluid communication through said second opening (7′).
 16. The embanking arrangement according to claim 8, wherein said pump (8) is configured for propelling and/or maneuvering of the port arrangement (1) when the inner tank of the port arrangement (1) is empty.
 17. The embanking arrangement according to claim 9, wherein said pump (8) is configured for propelling and/or maneuvering of the port arrangement (1) when the inner tank of the port arrangement (1) is empty.
 18. The embanking arrangement according to claim 10, wherein said pump (8) is configured for propelling and/or maneuvering of the port arrangement (1) when the inner tank of the port arrangement (1) is empty.
 19. The embanking arrangement according to claim 11, wherein said pump (8) is configured for propelling and/or maneuvering of the port arrangement (1) when the inner tank of the port arrangement (1) is empty.
 20. The embanking arrangement according to claim 13, wherein said pump (8) is configured for propelling and/or maneuvering of the port arrangement (1) when the inner tank of the port arrangement (1) is empty.
 21. The embanking arrangement according to claim 14, wherein said pump (8) is configured for propelling and/or maneuvering of the port arrangement (1) when the inner tank of the port arrangement (1) is empty.
 22. The embanking arrangement according to claim 15, wherein said pump (8) is configured for propelling and/or maneuvering of the port arrangement (1) when the inner tank of the port arrangement (1) is empty. 